1) Field of the Disclosure
The disclosure relates generally to coatings and methods for applying coatings, and in particular, to static dissipative coatings and methods for applying static dissipative coatings to fuel tank components.
2) Description of Related Art
The application of electrostatic (static) dissipative coatings onto conductive materials is known in a variety of industries, including the aerospace industry. Such static dissipative coatings may be applied to dissipate electrostatic charge that builds up on the surface of such conductive materials when the static dissipative coatings are provided with a point of discharge, such as an electrical path to ground. Insulating coatings may not adequately discharge the electrostatic charge, and the combination of insulating coatings on electrically-grounded conductive materials, or substrates, may create capacitance as electrostatic charges accumulate on the coating surfaces. Capacitance may result in spontaneous, self-initiated, electrical surface discharges when the electrostatic charges cannot relax to ground. These spontaneous, self-initiated, electrical surface discharges are also commonly known as propagating brush discharges (PBD). Propagating brush discharges are generally undesirable.
Known static dissipative coatings exist for use on glass-fiber reinforced plastic components on aircraft. However, such known static dissipative coatings can contain carbon black which can induce galvanic corrosion of aluminum.
In addition, a known method exists for applying an insulating primer on composite fuel tank surfaces of aircraft. However, to prevent propagating brush discharges (PBD), such known method requires extensive masking of the surface or substrate prior to applying the insulating primer, and further requires a striped primer configuration with specific stripe widths when applying the insulating primer. Thus, this known method can require additional labor and time to complete which can result in increased labor and manufacturing costs. Moreover, this known method may not allow the usage of glass-fiber reinforced plastic in the fuel tank which can result in extensive composite drill break-out, such as break-out caused by drilling of epoxy preimpregnated carbon fiber tape.
Accordingly, there is a need in the art for static dissipative fuel tank coatings and methods that provides advantages over known coatings and methods.